Carpenter ants excavate damp or decayed wood. A technician finds the nest, and the moisture that invited it, before treating.
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Carpenter ant control in Seattle means locating the nest, which is often in wet or decayed wood, treating it and fixing the moisture that attracted the ants. WSU Extension says they excavate wood rather than eat it. Seattle Pest Control connects King County callers with an independent local company; a same-day visit is offered when a technician is free.
Carpenter ants are large, dark ants that hollow out wood to make galleries for nesting. Washington State University's PestSense fact sheet is clear on the point that they do not eat wood, they excavate it, and that is why the damage looks like smooth tunnels rather than the rough, mud-packed galleries of termites. In a Puget Sound house the wood they choose is often already damp: a rotted sill, a window frame under a leaking gutter, a deck post, an old stump or a log pile close to the wall.
Finding the ants indoors does not mean the nest is indoors. WSU notes that the parent colony usually lives outdoors, and that many nests inside a house are satellite nests, which have no queen and depend on the colony elsewhere. That changes the job: killing the ants you see is rarely enough if the source is a stump twenty feet from the back door. Seattle Pest Control is a call line, answered 24/7, that connects you with an independent local pest-control company, and the visit is built around finding both the satellite and the parent.
They can be, especially where wood stays wet. WSU PestSense says carpenter ants excavate wood to nest, and the northwest's long wet season keeps sills, decks and crawl-space timber damp. No local count is available, so treat the risk as likely wherever there is rot, not as a number for any neighborhood.
The honest way to put it is that carpenter ants follow moisture and decay. A dry, sound house with no stumps nearby has less to offer them than a house with a leaking downspout and a mossy north wall. That is a statement about conditions, not a ranking of neighborhoods.
Old houses with wood-framed porches, additions and shaded corners offer more of the conditions than a recent build with tight detailing, though neither is immune. Trees touching a roof give ants a bridge, so branches are worth checking.
WSU PestSense gives April to early June as the swarming period. Winged males and females leave the nest to mate, and seeing winged ants indoors in spring may mean there is a nest in the building. Swarmers outside are less worrying than a cluster of them on a window sill inside.
Swarmers are easy to confuse with winged termites. Ants have a pinched waist, elbowed antennae and forewings longer than hind wings; termites have a thick waist, straight beads for antennae and wings of equal length. If you can keep one in a jar, the technician can confirm it.
A spring swarm is the time many homeowners first learn of the ants. It is a good reason to check the building for damp wood and to ask for a visit rather than waiting for the sawdust.
No. Carpenter ants excavate wood to make nesting galleries and push the shavings out, but they do not digest it. They feed on other insects, honeydew and household food. The damage comes from the tunnels, which can weaken a joist, sill or post over time, particularly when the wood is already rotting.
The difference matters for treatment. Because ants do not need the wood as food, poison on the wood alone does little. The plan targets the colony, whether that is through bait, direct nest treatment or both.
It also matters for the risk. Most carpenter ant damage is slow, and a small gallery in a window frame is a repair job, not a structural emergency. A technician can tell you whether the damage seen is minor, and when a contractor or engineer should look.
Remove stumps and rotting logs near the house and keep branches off the eaves, as WSU advises; fixing leaks and keeping firewood off the ground and away from walls help too. These are non-chemical steps. They lower the chance of a new colony settling, but they do not remove one that is already inside.
Trim shrubs so they do not touch siding, clear leaf litter from gutters and keep mulch a hand's width from the foundation. Check the crawl space with a flashlight in the dry months and note any wet insulation or sagging vapor barrier.
Do not spray ants you find. Contact sprays kill the foragers you see but may break a trail the technician wants to follow, and they rarely reach the nest.
Do not drill into a wall or pull out a section of trim to look for a nest unless you know where utilities run. Do not use foggers or flammable products. If a structural member such as a sill or beam sounds hollow and the floor above moves, have a contractor look before more work.
Note whether the ants are winged or wingless, the time of day, and the room or outside spot. A same-day visit is offered only when a technician is free, and no arrival time is promised.
Ants travel the same lines repeatedly. The technician watches a trail, often at dusk, and follows it to a tree, stump, fence post or gap in siding to find where the foraging workers come from.
Window sills, door frames, porch posts, the underside of decks and the sill plate seen from a crawl space are tapped and probed. Damp or soft wood is a priority because it is where a nest is most likely.
The technician judges whether the nest in the house is a satellite, whether a parent colony sits outdoors, or both. The answer decides where treatment goes and whether the yard needs work as well as the building.
The price is confirmed with you before treatment. Baits and targeted products are placed at trails and galleries, with label directions followed and your pets and children kept clear.
You are told which leak, gutter, vent or soil contact needs attention and whether rotted wood needs a carpenter. Without that step, new ants can find the same damp spot.
Where a nest can be found, the technician treats the gallery directly, which is usually the fastest route to ending activity in that spot. When the nest is inside a wall, small access holes may be needed, and the technician explains that first.
Workers carry bait back to the colony. This can reach a nest that cannot be seen, and it is often paired with trail work outdoors. It needs patience, because killing the foragers too quickly can leave the bait untouched.
Removing old stumps and rotting logs near the house, and trimming branches so they do not touch the eaves, are non-chemical steps WSU Extension lists. Treating an outdoor parent colony is a separate item and may be quoted separately.
If rot is the reason, treating ants without repairing the wood is half a job. The technician flags what needs replacing; construction repair, such as rebuilding framing, is trade work done by a contractor.
No outside price for carpenter ant work is printed here. These are the things that move a quote.
| Job | Typical range | What it includes |
|---|---|---|
| How many nests there are | Varies | One satellite nest in a window frame is simpler than several sites plus a parent colony outdoors |
| Where the nest sits | Depends on access | A wall void, a ceiling or a crawl space takes more time than a stump in the yard |
| Number of visits | One or several | Baiting often calls for a return visit to check whether activity has stopped |
| Outdoor work | Quoted separately | Treating an outdoor colony or clearing stumps and logs is separate from interior work |
| Wood repair | Contractor's price | Replacing damaged framing or trim is carpentry, not pest control |
Your exact price is confirmed on site before work starts. The Seattle cost guide explains what moves a quote.
If it's an emergency, call now. For non-urgent carpenter ant control, send the form and we'll call you back.
Puget Sound homes live under conifers. Properties around Medina, Mercer Island and the Lake Washington shoreline often have mature trees, hedges, docks and shaded decks, which provide the wet and decayed wood WSU links to carpenter ants. A stump left from a past tree removal can be the colony's home for years.
Older Seattle houses add a second pathway. Many have crawl spaces, wood porches that were added later and original window sills that have taken decades of rain. Where the paint is cracked, water can enter and soften a sill, and that is the sort of spot a technician checks first.
Swarms fall in April through early June, a period that tends to coincide with the end of the wet season, so the sight of winged ants can follow a long stretch of damp weather. That is a common pattern, not a promise, and each year differs.
Small yellowish-brown ants in damp wood are a sign of a moisture problem. The fix is the colony and the water that feeds it.
A visit that maps leaks, ventilation and wood-to-soil contact so ants and termites lose the damp wood they look for.
Kitchen and foundation ants identified and baited, with the trail followed back to the nest and the entry sealed.
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Carpenter ants are large and dark and excavate wood to nest; moisture ants are small, light yellowish-brown and nest in damp rotting wood or soil.
Termites exist in western Washington but are generally considered less common than in warmer states, and no local count is available.
Around Seattle, carpenter ants swarm from April to early June, yellowjackets are most troublesome in August and September, dampwood termites swarm in late summer or fall after rain, and the wet season from roughly October to March brings damp-wood and rodent concerns.
Look at the waist and the antennae. Ants have a narrow, pinched waist and elbowed antennae; termites have a thick, straight body and straight antennae. The technician can confirm from a single insect or from the way the wood is excavated.
It might be, but WSU notes the parent colony is usually outdoors and many indoor nests are satellites. The technician looks inside and out. Finding where the foragers come from is the main task of the first visit.
Sometimes, if a nest is found and treated. Baiting and colonies with several sites often need a return visit. The technician tells you which this is and what to watch for between visits.
If the ants have hollowed structural wood or the wood has rotted, probably yes. Pest control treats the ants; replacing framing is carpentry. The technician points out what looks sound and what does not.
They can bite if disturbed, but the usual concern is damage to wood rather than health. Keep children and pets away from treated areas as the label directs.
Yes. Moisture ants are smaller, yellowish-brown and nest in damp rotting wood or soil. See moisture ant control if the ants you see are small and pale.